Control system for hydraulic winches



Oct. 11, 1966 s Dz 3,278,161

CONTROL SYSTEM FOR HYDRAULIC WINCHES Filed NOV. 13, 1963 2 Sheets-Sheet l INVENTOR:

' HARRY 5A N00).

Oct. 11, 1966 H. SANDZY 3,278,161

CONTROL SYSTEM FOR HYDRAULIC WINCHES Filed NOV. 13, 1965 2 Sheets-Sheet 2 INVENTOR HARRY SA N002 United States Patent 8 Claims. cl. 254 1s3) This invention relates to control systems for hydraulic winches and in particular, is concerned with the manual control of such winches. Normally this control is effected by means of a control handle arranged on the said winch at the side of its manual control valve. However it is often desirable to be able to carry out the control from a position remote from said winch. It is then well-known to connect up a remote control system which transmits the movement from a control handle of a control column over to the manual control valve or its control handle. This can be effected by means of an electric, pneumatic or hydraulic transmission. An electric transmission will however be complicated and expensive, and is not employed in practice. The pneumatic controls require suitable compressed air apparatus, and previously known hydraulic remote control apparatus has suffered from the disadvantage that it requires rather a lot of power to operate it. An additional disadvantage with hydraulic remote control apparatus is that it very often gets out of balance, that is to say the middle position of the manual control valve does not correspond to the middle position of the remote control handle, and vice versa. Also there is the further disadvantage that it can be very difiicult to adjust to intermediate positions, for example for hoisting at a reduced speed.

An object of the invention is to provide a control system for hydraulic winches, wherein very little power is needed for operation, and wherein it is ensured that the manual control valve of the winch will always be found in the correct position in relation to the remote control handle, even in arbitrary intermediate positions.

Accordingly the present invention consists in a control system for hydraulic winches, wherein a manual control valve of the winch is adapted to be brought into required positions for hoisting, stop and letting out by a hydraulic remote control, the hydraulic remote control system comprising a driving pump independent of the main circuit of the winch which supplies driving oil in separate circuit for displacement of the primary side in a servocontrol system, whose secondary side is connected to the control valve of the winch.

In order that the invention can be more clearly understood, a convenient embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a control system for loading and unloading equipment on a ship, consisting of a cargo winch and two winches for topping and swinging the boom.

FIG. 2 is a section through a control column which is included in the system according to FIG. 1.

FIG. 3 is a section on a larger scale through a servoarrangement which is employed in the system according to FIGS. 1 and 2.

FIG. 4 shows a part of a section through the manual control valve.

Referring to FIG. 1 the winch equipment includes an electric motor which drives an hydraulic pump 11 through a toothed wheel transmission 12 and a coupling 13. The tube conduits 14, 15 run to and from the pump up to a cargo winch represented generally by 16, and from there to two combined topping and boom swinging winches 17 and 18 respectively, wherein only their manual control valves are illustrated.

The winches each have a control handle 19, which by a non-visible link arm mechanism is connected to the manual control slide in the interior of the valve housing 20. In addition a hydraulic cylinder 21 is arranged at the top of the valve housing.

The electric motor 10 in addition drives a servo-pump 22, which receives hydraulic driving medium from the supply conduit 14 through a conduit 23, and supplies driving medium under pressure to a conduit 24. This conduit leads over to and branches otf to two control columns 25, 26, which are arranged at a position remote from the winches 16, 17 and 18, and which each have respective control handles 27 and 28. The control column 25 having handle 27 serves as the remote control for the cargo winch 16, while the other control column 26 with its handle 28 serves as the remote control for the two topping and boom swinging winches 17 and 18. In order to obtain this last-mentioned control of the two winches with a single handle, the handle is arranged to be pivoted in a vertical direction as well as in a horizontal direction.

A section through a control column is shown in FIG. 2. The conduit 24 is led into the control column through a nipple 29 which is connected to a flexible high pressure pipe 30. This leads to a servo-control valve 31, which is axially displaceably arranged on a piston rod 32 which is associated with a servo-cylinder 33. The servo-control valve 31 is reciprocable in the axial direction by means of a control rod 34, which is connected to a manual control handle 28 through a link arm connection not shown.

A section through the servo-control valve 31 and the associated servo-cylinder 33 is shown in FIG. 3. The flexible high pressure pipe is connected through a nipple 35 to a bore 36 which leads into a centrally situated annular cavity 37. On each side of this annular cavity 37 there are situated two other annular cavities 38, 39. The piston rod 32 passes through the through bore 40 in the servo-control valve and thereby seals otf these three annular cavities 37, 38, 39 from each other. The tWo annular cavities 38, 39 are in connection with a return conduit back to the pump 11 through channels not shown in FIG. 3.

In the piston rod 32 there are two separate channels 41, 42. Each channel is provided with an opening 43, 44 respectively, arranged so that in a middle position, connection is obtained between the central annular cavity 37 and the annular cavities 33, 39. On'moving the servocontrol valve out of the middle position however one opening, for example opening 43, will come into selective connection only with the central annular cavity, while the other opening comes into selective connection only with one of the outer annular cavities 38, 39 and is no longer in communication with the central cavity. This action will be explained later.

The piston rod 32 runs axially through the servocylinder 33, which comprises a first chamber divided into two part-chambers 45, 46 by a piston 47 secured on the piston rod 32. The axial channel 41 of the piston rod 32 discharges into the part-chamber through an opening 48, and the other axial channel 42 discharges into the other partchamber 46 through a second opening 4-9. The servo-cylinder in addition includes a second chamber which is also divided into two part-chambers 50 and 51 by a piston 52 secured on the piston rod 32. This piston in addition slides on a guide rod 53 having an inner bore 54, from which lead two small bores 55, 56 to each side of the piston 52, when this is located in the middle position. As soon as the piston is moved 3 out of the middle position, however one of these bores will be closed.

A conduit 57 leads from the part-chamber 50, and from the part-chamber 51 there leads a conduit 58, which conduits are led to the hydraulic cylinder 21 at the top of the housing of the manual control valve, the conduits 57, 58 being connected respectively to the upper side and the lower side of the piston 59 in cylinder 21 (see FIG. 4

The mode of operation of the arrangement is as follows:

The servo-pump 22 will supply driving medium through the central annular cavity 37 and over to both the annular cavities 38, 39 through openings 43, 44, when the handle 28, and with it the servo-control valve 31 also, are located at rest in the middle position, in this respect as seen in FIG. 3 the openings 43, 44 are sufficiently large to establish communication between the central cavity 37 and the cavities 38, 39 when the valve 31 is in its middle position. However, upon movement in either direction of the valve 31, one of the openings will be disconnected from the central cavity 37. Thus if the handle 28 is moved out of the middle position, for example to the left in FIG. 3, the opening 44 will be placed in selective connection with the annular cavity 37 and be out of communication with cavity 39 (the left cavity). Opening 43 will be in communication with cavity 38 only this causes pressure medium to be fed only to the axial channel 42 and thereby to the part chamber 46 on the right side of the piston 47. This will move the piston rod 32 to the left. In this way the pressure medium is forced out of the left part-chamber 51, through the conduit 58 and to the cylinder 21, whose piston 59 is moved upwards. The piston 59 has a rod which is connected to a manual control slide 65 to operate the same together with the piston 59. Thus when the piston 59 is moved upwards, the slide of the manual control valve is moved, for example, to the hoisting position. Similarly, if the handle 28 is moved to the right this will cause pressure medium to be fed to partchamber 45 to cause piston rod 32 to be moved to the right which causes pressure medium to be forced out of part-chamber 50 through conduit 57 to cylinder 21 to lower piston 59 therein.

It has been explained before that when the servocontrol valve is moved for example to the left, the piston rod will also be moved to the left. If the servo-control valve 31 is now stopped a short distance from the middle position, this movement of the piston rod will cause the two openings 48, 49 to be moved relative to the annular cavities 37, 38, 39, whereby balance in the system is obtained again. The piston rod is moved in other words a correspondingly short distance from the middle position, and remains stationary in this position.

This will again involve only a small amount of pressure oil being fed to the cylinder 21 for movement of the control slide out of the middle position and in the direction of the hoisting position. The control slide will be moved a distance which will be proportional to the distance the servo-control valve is moved, and it will therefore be able to be adjusted to arbitrary intermediate positions.

When the piston is moved back to the middle position or the stop position, the two bores 55, 56 will enable a balancing of any possible difference in pressure between the two sides of the piston 52. In this way centering of the system is obtained. It can be mentioned that the control handles 27, 28 are provided with oppositely directed springs as well as the slide of the manual control valve which urge these parts towards the middle position.

In connection with the annular cavity 37 there is also provided an excess pressure valve in the form of a ball 60 in a bore 61. The ball is normally pressed by a pressure spring 62 against its seating. At a suitable excess pressure, for example about 20 kg./cm. the ball is lifted from its seating and allows the passage of oil to a bore 63 to one of the annular cavities 38, 39. These as was stated earlier are in connection with the return line to the pump 11. This return line is preferably eflected through a conduit 64, which passes over to the return conduit 15 of the main pump. Essentially therefore, the lines 24, 64 form a separate fluid circuit for the servo-control valve 31, the servo cylinder 33 and the hydraulic cylinder 21.

The said manual control slide, which is shown at 65 in FIG. 4, may be of the kind which is illustrated in Norwegian Patent No. 93,277.

What I claim is:

1. In a control system for hydraulic winches, wherein a manual control valve of the Winch is adapted to be brought into required positions for hoisting, stopping, and letting out by a hydraulic remote control system, said hydraulic remote control system comprising a driving pump and a servo-control system for operating the manual control valve, said driving pump supplying driving fluid in a separate circuit to said servo-control system, said servo-control system including a displaceable primary stage which is driven by the driving fluid and a secondary stage controlled by the primary stage and adapted for connection to the manual control valve of the winch to operate the same and the winch thereby, said primary stage including a servo-control valve, the driving pump supplying driving fluid to the servo-control valve, a piston rod supporting said servo-control valve for axial displacement thereof, a cylinder having a driving piston, said cylinder receiving the piston rod for axial displacement therein in opposite directions such that movement of said piston rod causes movement of said piston in respectively opposite directions in either of which fluid for the adjustment of the control valve is supplied.

2. In a control system according to claim 1 wherein the manual control valve comprises a slide axially displaceable in a housing and there is arranged on the valve housing coaxially with the slide a hydraulic cylinder with associated piston, the piston rod of which is connected to the slide.

3. In a control system according to claim 1 wherein the servo-control valve has three cavities, of which a middle one is connected with the pressure side of the driving pump and the other two with its return side, and the piston rod has two channels which on the one hand are connected with each side of the driving piston and on the other hand upon displacement of the servo-control valve the channels can be brought into connection with the central cavity and one of the other cavities respectively.

4. A control system according to claim 1 wherein the primary stage of the servo-control system further comprises an accompanying piston on said piston rod, movement of said accompanying piston supplying the driving fluid to the secondary stage for the adjustment of the manual control valve.

5. A control system according to claim 1 comprising a Winch arrangement comprising a cargo winch together with two other winches, and two remote control columns each having a control handle, one handle serving for the remote control of the cargo winch, and the other serving for the control of both of the other two winches.

6. A control system according to claim 5 wherein one control handle is movable in one plane while the other handle is movable in two mutually crossing planes, movements in the one crossing plane serving for control of one of the two winches, while the movement in the other crossing plane serving for the control of the other winch.

7. In a control system for a hydraulic winch having a control valve; hydraulic remote control means comprising a manual control lever, pump means for supplying a pressure medium, and servo-control means coupled to said pump means and to the manual control lever for being the first means and has a centered position with respect 10 to the first means in which the servo-control means is at rest, said first means being displaceable by the manual control lever with respect to said support means to selectively open only one of said passages, said second means undergoing displacement in a direction by the opening of said selected one passage to return to the centered position thereof.

8. In a system as claimed in claim 7 wherein said second means delivers pressure medium upon its displacement for operating the control valve such that the direction of displacement of the second means controls the direction of drive of the hydraulic Winch.

References Cited by the Examiner UNITED STATES PATENTS 2,258,307 10/1941 Vickers 254186 2,823,897 2/1958 Kellogg 254-173 3,154,199 10/1964 Balogh.

FOREIGN PATENTS 969,019 6/1962, Great Britain.

15 EVON C. BLUNK, Primary Examiner.

SAMUEL F. COLEMAN, Examiner.

H. C. HORNSBY, Assistant Examiner. 

1. IN A CONTROL SYSTEM FOR HYDRAULIC WINCHES, WHEREIN A MANUAL CONTROL VALVE OF THE WINCH IS ADAPTED TO BE BROUGH INTO REQUIRED POSITIONS FOR HOISTING, STOPPING, AND LETTING OUT BY A HYDRAULIC REMOTE CONTROL SYSTEM, SAID HYDRAULIC REMOTE CONTROL SYSTEM COMPRISING A DRIVING PUMP AND A SERVO-CONTROL SYSTEM FOR OPERATING THE MANUAL CONTROL VALVE, SAID DRIVING PUMP SUPPLYING DRIVING FLUID IN A SEPARATE CIRCUIT TO SAID SERVO-CONTROL SYSTEM, SAID SERVO-CONTROL SYSTEM INCLUDING A DISPLACEABLE PRIMARY STAGE WHICH IS DRIVEN BY THE DRIVING FLUID AND A SECONDARY STAGE CONTROLLED BY THE PRIMARY STAGE AND ADAPTED FOR CONNECTION TO THE MANUAL CONTROL VALVE OF THE WINCH TO OPERATE THE SAME AND THE WINCH THEREBY, SAID PRIMARY STAGE INCLUDING A SERVO-CONTROL VALVE, THE DRIVING PUMP SUPPLYING DRIVING FLUID TO THE SERVO-CONTROL VALVE, A PISTON ROD SUPPORTING SAID SERVO-CONTROL VALVE FOR AXIAL DISPLACEMENT THEREOR, A CYLINDER HAVING A AXIAL DISPLACEMENT CYLINDER RECEIVING THE PISTON ROD FOR AXIAL DISPLACEMENT THEREIN IN OPPOSITE DIRECTIONS SUCH THAT MOVEMENT OF SAID PISTON ROD CAUSES MOVEMENT OF SAID PISTON IN RESPECTIVELY OPPOSITE DIRECTIONS IN EITHER OF WHICH FLUID FOR THE ADJUSTMENT OF THE CONTROL VALVE IS SUPPLIED. 